Conventionally, in the case of sewing a fastener stringer or a fastener chain to which a coil-shaped continuous element made of a synthetic resin is sewn to various attached bodies such as a cloth and the like, a sewing process has been carried out by using a sewing machine having a sewing machine foot, for example, as disclosed in Japanese Utility Model Publication No. 51-95459 (Patent Document 1).
In this case, a description will be given briefly of a method of sewing a fastener chain to which a continuous element is sewn to an attached body by using a sewing machine foot which is disclosed in the Patent Document 1.
First of all, as shown in FIG. 10, a fastener chain 51 is arranged in such a manner that a continuous element 52 is arranged in an upper side of a fastener tape 53, and an attached body 54 is further superposed in a state of being bent in a U-shape, on the fastener tape 53 of the fastener chain 51. At this time, the continuous element 52 and the U-shaped bent attached body 54 are arranged in the same tape surface side of the fastener tape 53.
In a state in which the attached body 54 is superposed on the fastener tape 53 of the fastener chain 51 as mentioned above, the fastener tape 53 and the attached body 54 are conveyed between a sewing machine head 55 of a sewing machine and a throat plate which is not illustrated. Further, the fastener tape 53 and the attached body 54 are thrust by a sewing machine needle 56 so as to be sewn to each other while pressing the fastener tape 53 and the attached body 54 by the sewing machine foot 55, whereby the fastener chain 51 can be sewn to the attached body 54.
In the case that the fastener chain 51 is sewn to the attached body 54 as mentioned above, it is demanded to make a bent section 54a of the attached body 54, which is bent in a U-shape, close to the continuous element 52 of the fastener chain 51 and accurately carry out a sewing while forming a sewing line (a stitch line) sewing the fastener tape 53 to the attached body 54 substantially in parallel to the continuous element 52, for example, in order to enhance an outer appearance quality of a product to which the fastener is attached. On the other hand, since a thrusting position of the sewing machine needle 56 and the vicinity thereof are concealed by the sewing machine foot 55 in the case that the sewing is carried out by the sewing machine, it has been hard to accurately carry out the sewing as mentioned above.
Accordingly, in the Patent Document 1, the sewing machine foot 55 installed to the sewing machine is constructed by using a transparent material (for example, a transparent synthetic resin material). In accordance with this, it is possible to easily view the thrusting portion of the sewing machine needle 56 and the vicinity thereof via the transparent sewing machine foot 55 at a time of sewing. In accordance with this, it is possible to make the U-shaped bent section 54a of the attached body 54 close to the continuous element 52, and it is possible to accurately carry out the sewing in such a manner that the sewing line is arranged substantially in parallel to the continuous element 52.
Even in this case, it is necessary for the sewing machine foot 55 to stably press the fastener tape 53 and the attached body 54 from the above at a time of sewing, and it is necessary that the sewing machine foot 55 itself has a predetermined strength. Accordingly, it has been necessary for the sewing machine foot 55 to be formed in such a manner that a dimension in a width direction (a lateral direction) is secured at a predetermined size or more. In accordance with this, it is necessary for the sewing line to be set at a position which is spaced at a predetermined distance from the continuous element 52, in such a manner as to prevent the sewing machine foot 55 and the continuous element 52 from being interfered at a time of sewing, and there has been a limit to make the U-shaped bent section 54a of the attached body 54 close to the continuous element 52.
In this case, in the slide fastener having the continuous element 52 as shown in FIG. 10, the continuous element 52 is arranged in an outer surface (an exposed surface) side of the fastener attached product, at a time when it is attached to the attached body 54, the continuous element 52 comes to a state in which it is exposed to an external portion in an ordinary manner of use.
However, in recent years, the slide fastener has come to be widely used, for example, in a sitting seat for a motor vehicle and the like, as well as the clothes. In accordance with this, in some product to which the slide fastener is attached, there has been a case that it is desirable to conceal the continuous element in such a manner as to be prevented from being exposed to the external portion, in the light of a design or the like.
In order to respond to the demand mentioned above, there has been known a slide fastener of a concealed type (a concealed slide fastener) which can shield the continuous element by the fastener tape so as to be invisible from an outer surface side (refer, for example, to Japanese Patent Application Laid-Open No. 2006-015069 (Patent Document 2) and the like).
Typically, the concealed slide fastener has a pair of right and left fastener tapes, coil-shaped or zigzag-shaped continuous elements which are respectively sewn to the fastener tapes, and sliders which are arranged so as to be slidable along the right and left continuous elements. In this case, the fastener tape has a tape main body portion and an element attaching portion which is arranged in a side of one side edge of the tape main body portion, and the tape main body portion in a side of the element attaching portion is bent in a U-shape in a tape width direction, whereby a bent section is formed.
The continuous element has an engagement head, upper and lower leg portions which are extended from the engagement head, and a connecting portion (which is also called as a reverse portion) which connects between leg portions of the elements which are adjacent to each other. The continuous element is attached by sewing the upper and lower leg portions to an element attaching portion of the fastener tape, in a state in which the engagement head is directed to the side of the tape main body portion of the fastener tape. In accordance with this, since the fastener tape is bent in a U-shape as mentioned above, it comes to a state in which the engagement head of the continuous element protrudes toward an outer side from the U-shaped bent section of the fastener tape.
In accordance with the concealed slide fastener mentioned above, the U-shaped bent sections of the right and left fastener tapes are confronted to each other by sliding the slider so as to engage the right and left continuous elements with each other. In accordance with this, the right and left continuous elements in the engaged state can be concealed in such a manner as to be invisible from the tape exposure surface side of the fastener tape, by the fastener tape in which the bent sections thereof are confronted to each other.
Accordingly, the concealed slide fastener is preferably used in the product such as the various clothes, shoes and the like, by taking advantage of not precluding a design of the product with its concealment, and has further come to be used in a seat cover for a sitting seat of a motor vehicle, a train and the like, in recent years.